config.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  * Copyright (C) Johannes Schindelin, 2005
   6  *
   7  */
   8 #include "cache.h"
   9 #include <regex.h>
  10
  11 #define MAXNAME (256)
  12
  13 static FILE *config_file;
  14 static const char *config_file_name;
  15 static int config_linenr;
  16 static int get_next_char(void)
  17 {
  18         int c;
  19         FILE *f;
  20
  21         c = '\n';
  22         if ((f = config_file) != NULL) {
  23                 c = fgetc(f);
  24                 if (c == '\r') {
  25                         /* DOS like systems */
  26                         c = fgetc(f);
  27                         if (c != '\n') {
  28                                 ungetc(c, f);
  29                                 c = '\r';
  30                         }
  31                 }
  32                 if (c == '\n')
  33                         config_linenr++;
  34                 if (c == EOF) {
  35                         config_file = NULL;
  36                         c = '\n';
  37                 }
  38         }
  39         return c;
  40 }
  41
  42 static char *parse_value(void)
  43 {
  44         static char value[1024];
  45         int quote = 0, comment = 0, len = 0, space = 0;
  46
  47         for (;;) {
  48                 int c = get_next_char();
  49                 if (len >= sizeof(value))
  50                         return NULL;
  51                 if (c == '\n') {
  52                         if (quote)
  53                                 return NULL;
  54                         value[len] = 0;
  55                         return value;
  56                 }
  57                 if (comment)
  58                         continue;
  59                 if (isspace(c) && !quote) {
  60                         space = 1;
  61                         continue;
  62                 }
  63                 if (!quote) {
  64                         if (c == ';' || c == '#') {
  65                                 comment = 1;
  66                                 continue;
  67                         }
  68                 }
  69                 if (space) {
  70                         if (len)
  71                                 value[len++] = ' ';
  72                         space = 0;
  73                 }
  74                 if (c == '\\') {
  75                         c = get_next_char();
  76                         switch (c) {
  77                         case '\n':
  78                                 continue;
  79                         case 't':
  80                                 c = '\t';
  81                                 break;
  82                         case 'b':
  83                                 c = '\b';
  84                                 break;
  85                         case 'n':
  86                                 c = '\n';
  87                                 break;
  88                         /* Some characters escape as themselves */
  89                         case '\\': case '"':
  90                                 break;
  91                         /* Reject unknown escape sequences */
  92                         default:
  93                                 return NULL;
  94                         }
  95                         value[len++] = c;
  96                         continue;
  97                 }
  98                 if (c == '"') {
  99                         quote = 1-quote;
 100                         continue;
 101                 }
 102                 value[len++] = c;
 103         }
 104 }
 105
 106 static int get_value(config_fn_t fn, char *name, unsigned int len)
 107 {
 108         int c;
 109         char *value;
 110
 111         /* Get the full name */
 112         for (;;) {
 113                 c = get_next_char();
 114                 if (c == EOF)
 115                         break;
 116                 if (!isalnum(c))
 117                         break;
 118                 name[len++] = tolower(c);
 119                 if (len >= MAXNAME)
 120                         return -1;
 121         }
 122         name[len] = 0;
 123         while (c == ' ' || c == '\t')
 124                 c = get_next_char();
 125
 126         value = NULL;
 127         if (c != '\n') {
 128                 if (c != '=')
 129                         return -1;
 130                 value = parse_value();
 131                 if (!value)
 132                         return -1;
 133         }
 134         return fn(name, value);
 135 }
 136
 137 static int get_extended_base_var(char *name, int baselen, int c)
 138 {
 139         do {
 140                 if (c == '\n')
 141                         return -1;
 142                 c = get_next_char();
 143         } while (isspace(c));
 144
 145         /* We require the format to be '[base "extension"]' */
 146         if (c != '"')
 147                 return -1;
 148         name[baselen++] = '.';
 149
 150         for (;;) {
 151                 int c = get_next_char();
 152                 if (c == '\n')
 153                         return -1;
 154                 if (c == '"')
 155                         break;
 156                 if (c == '\\') {
 157                         c = get_next_char();
 158                         if (c == '\n')
 159                                 return -1;
 160                 }
 161                 name[baselen++] = c;
 162                 if (baselen > MAXNAME / 2)
 163                         return -1;
 164         }
 165
 166         /* Final ']' */
 167         if (get_next_char() != ']')
 168                 return -1;
 169         return baselen;
 170 }
 171
 172 static int get_base_var(char *name)
 173 {
 174         int baselen = 0;
 175
 176         for (;;) {
 177                 int c = get_next_char();
 178                 if (c == EOF)
 179                         return -1;
 180                 if (c == ']')
 181                         return baselen;
 182                 if (isspace(c))
 183                         return get_extended_base_var(name, baselen, c);
 184                 if (!isalnum(c) && c != '.')
 185                         return -1;
 186                 if (baselen > MAXNAME / 2)
 187                         return -1;
 188                 name[baselen++] = tolower(c);
 189         }
 190 }
 191
 192 static int git_parse_file(config_fn_t fn)
 193 {
 194         int comment = 0;
 195         int baselen = 0;
 196         static char var[MAXNAME];
 197
 198         for (;;) {
 199                 int c = get_next_char();
 200                 if (c == '\n') {
 201                         /* EOF? */
 202                         if (!config_file)
 203                                 return 0;
 204                         comment = 0;
 205                         continue;
 206                 }
 207                 if (comment || isspace(c))
 208                         continue;
 209                 if (c == '#' || c == ';') {
 210                         comment = 1;
 211                         continue;
 212                 }
 213                 if (c == '[') {
 214                         baselen = get_base_var(var);
 215                         if (baselen <= 0)
 216                                 break;
 217                         var[baselen++] = '.';
 218                         var[baselen] = 0;
 219                         continue;
 220                 }
 221                 if (!isalpha(c))
 222                         break;
 223                 var[baselen] = tolower(c);
 224                 if (get_value(fn, var, baselen+1) < 0)
 225                         break;
 226         }
 227         die("bad config file line %d in %s", config_linenr, config_file_name);
 228 }
 229
 230 int git_config_int(const char *name, const char *value)
 231 {
 232         if (value && *value) {
 233                 char *end;
 234                 int val = strtol(value, &end, 0);
 235                 if (!*end)
 236                         return val;
 237         }
 238         die("bad config value for '%s' in %s", name, config_file_name);
 239 }
 240
 241 int git_config_bool(const char *name, const char *value)
 242 {
 243         if (!value)
 244                 return 1;
 245         if (!*value)
 246                 return 0;
 247         if (!strcasecmp(value, "true"))
 248                 return 1;
 249         if (!strcasecmp(value, "false"))
 250                 return 0;
 251         return git_config_int(name, value) != 0;
 252 }
 253
 254 int git_default_config(const char *var, const char *value)
 255 {
 256         /* This needs a better name */
 257         if (!strcmp(var, "core.filemode")) {
 258                 trust_executable_bit = git_config_bool(var, value);
 259                 return 0;
 260         }
 261
 262         if (!strcmp(var, "core.ignorestat")) {
 263                 assume_unchanged = git_config_bool(var, value);
 264                 return 0;
 265         }
 266
 267         if (!strcmp(var, "core.prefersymlinkrefs")) {
 268                 prefer_symlink_refs = git_config_bool(var, value);
 269                 return 0;
 270         }
 271
 272         if (!strcmp(var, "core.logallrefupdates")) {
 273                 log_all_ref_updates = git_config_bool(var, value);
 274                 return 0;
 275         }
 276
 277         if (!strcmp(var, "core.warnambiguousrefs")) {
 278                 warn_ambiguous_refs = git_config_bool(var, value);
 279                 return 0;
 280         }
 281
 282         if (!strcmp(var, "user.name")) {
 283                 safe_strncpy(git_default_name, value, sizeof(git_default_name));
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "user.email")) {
 288                 safe_strncpy(git_default_email, value, sizeof(git_default_email));
 289                 return 0;
 290         }
 291
 292         if (!strcmp(var, "i18n.commitencoding")) {
 293                 safe_strncpy(git_commit_encoding, value, sizeof(git_commit_encoding));
 294                 return 0;
 295         }
 296
 297         /* Add other config variables here and to Documentation/config.txt. */
 298         return 0;
 299 }
 300
 301 int git_config_from_file(config_fn_t fn, const char *filename)
 302 {
 303         int ret;
 304         FILE *f = fopen(filename, "r");
 305
 306         ret = -1;
 307         if (f) {
 308                 config_file = f;
 309                 config_file_name = filename;
 310                 config_linenr = 1;
 311                 ret = git_parse_file(fn);
 312                 fclose(f);
 313                 config_file_name = NULL;
 314         }
 315         return ret;
 316 }
 317
 318 int git_config(config_fn_t fn)
 319 {
 320         return git_config_from_file(fn, git_path("config"));
 321 }
 322
 323 /*
 324  * Find all the stuff for git_config_set() below.
 325  */
 326
 327 #define MAX_MATCHES 512
 328
 329 static struct {
 330         int baselen;
 331         char* key;
 332         int do_not_match;
 333         regex_t* value_regex;
 334         int multi_replace;
 335         off_t offset[MAX_MATCHES];
 336         enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
 337         int seen;
 338 } store;
 339
 340 static int matches(const char* key, const char* value)
 341 {
 342         return !strcmp(key, store.key) &&
 343                 (store.value_regex == NULL ||
 344                  (store.do_not_match ^
 345                   !regexec(store.value_regex, value, 0, NULL, 0)));
 346 }
 347
 348 static int store_aux(const char* key, const char* value)
 349 {
 350         switch (store.state) {
 351         case KEY_SEEN:
 352                 if (matches(key, value)) {
 353                         if (store.seen == 1 && store.multi_replace == 0) {
 354                                 fprintf(stderr,
 355                                         "Warning: %s has multiple values\n",
 356                                         key);
 357                         } else if (store.seen >= MAX_MATCHES) {
 358                                 fprintf(stderr, "Too many matches\n");
 359                                 return 1;
 360                         }
 361
 362                         store.offset[store.seen] = ftell(config_file);
 363                         store.seen++;
 364                 }
 365                 break;
 366         case SECTION_SEEN:
 367                 if (strncmp(key, store.key, store.baselen+1)) {
 368                         store.state = SECTION_END_SEEN;
 369                         break;
 370                 } else
 371                         /* do not increment matches: this is no match */
 372                         store.offset[store.seen] = ftell(config_file);
 373                 /* fallthru */
 374         case SECTION_END_SEEN:
 375         case START:
 376                 if (matches(key, value)) {
 377                         store.offset[store.seen] = ftell(config_file);
 378                         store.state = KEY_SEEN;
 379                         store.seen++;
 380                 } else {
 381                         if (strrchr(key, '.') - key == store.baselen &&
 382                               !strncmp(key, store.key, store.baselen)) {
 383                                         store.state = SECTION_SEEN;
 384                                         store.offset[store.seen] = ftell(config_file);
 385                         }
 386                 }
 387         }
 388         return 0;
 389 }
 390
 391 static void store_write_section(int fd, const char* key)
 392 {
 393         const char *dot = strchr(key, '.');
 394         int len1 = store.baselen, len2 = -1;
 395
 396         dot = strchr(key, '.');
 397         if (dot) {
 398                 int dotlen = dot - key;
 399                 if (dotlen < len1) {
 400                         len2 = len1 - dotlen - 1;
 401                         len1 = dotlen;
 402                 }
 403         }
 404
 405         write(fd, "[", 1);
 406         write(fd, key, len1);
 407         if (len2 >= 0) {
 408                 write(fd, " \"", 2);
 409                 while (--len2 >= 0) {
 410                         unsigned char c = *++dot;
 411                         if (c == '"')
 412                                 write(fd, "\\", 1);
 413                         write(fd, &c, 1);
 414                 }
 415                 write(fd, "\"", 1);
 416         }
 417         write(fd, "]\n", 2);
 418 }
 419
 420 static void store_write_pair(int fd, const char* key, const char* value)
 421 {
 422         int i;
 423
 424         write(fd, "\t", 1);
 425         write(fd, key+store.baselen+1,
 426                 strlen(key+store.baselen+1));
 427         write(fd, " = ", 3);
 428         for (i = 0; value[i]; i++)
 429                 switch (value[i]) {
 430                 case '\n': write(fd, "\\n", 2); break;
 431                 case '\t': write(fd, "\\t", 2); break;
 432                 case '"': case '\\': write(fd, "\\", 1);
 433                 default: write(fd, value+i, 1);
 434         }
 435         write(fd, "\n", 1);
 436 }
 437
 438 static int find_beginning_of_line(const char* contents, int size,
 439         int offset_, int* found_bracket)
 440 {
 441         int equal_offset = size, bracket_offset = size;
 442         int offset;
 443
 444         for (offset = offset_-2; offset > 0
 445                         && contents[offset] != '\n'; offset--)
 446                 switch (contents[offset]) {
 447                         case '=': equal_offset = offset; break;
 448                         case ']': bracket_offset = offset; break;
 449                 }
 450         if (bracket_offset < equal_offset) {
 451                 *found_bracket = 1;
 452                 offset = bracket_offset+1;
 453         } else
 454                 offset++;
 455
 456         return offset;
 457 }
 458
 459 int git_config_set(const char* key, const char* value)
 460 {
 461         return git_config_set_multivar(key, value, NULL, 0);
 462 }
 463
 464 /*
 465  * If value==NULL, unset in (remove from) config,
 466  * if value_regex!=NULL, disregard key/value pairs where value does not match.
 467  * if multi_replace==0, nothing, or only one matching key/value is replaced,
 468  *     else all matching key/values (regardless how many) are removed,
 469  *     before the new pair is written.
 470  *
 471  * Returns 0 on success.
 472  *
 473  * This function does this:
 474  *
 475  * - it locks the config file by creating ".git/config.lock"
 476  *
 477  * - it then parses the config using store_aux() as validator to find
 478  *   the position on the key/value pair to replace. If it is to be unset,
 479  *   it must be found exactly once.
 480  *
 481  * - the config file is mmap()ed and the part before the match (if any) is
 482  *   written to the lock file, then the changed part and the rest.
 483  *
 484  * - the config file is removed and the lock file rename()d to it.
 485  *
 486  */
 487 int git_config_set_multivar(const char* key, const char* value,
 488         const char* value_regex, int multi_replace)
 489 {
 490         int i, dot;
 491         int fd = -1, in_fd;
 492         int ret;
 493         char* config_filename = strdup(git_path("config"));
 494         char* lock_file = strdup(git_path("config.lock"));
 495         const char* last_dot = strrchr(key, '.');
 496
 497         /*
 498          * Since "key" actually contains the section name and the real
 499          * key name separated by a dot, we have to know where the dot is.
 500          */
 501
 502         if (last_dot == NULL) {
 503                 fprintf(stderr, "key does not contain a section: %s\n", key);
 504                 ret = 2;
 505                 goto out_free;
 506         }
 507         store.baselen = last_dot - key;
 508
 509         store.multi_replace = multi_replace;
 510
 511         /*
 512          * Validate the key and while at it, lower case it for matching.
 513          */
 514         store.key = (char*)malloc(strlen(key)+1);
 515         dot = 0;
 516         for (i = 0; key[i]; i++) {
 517                 unsigned char c = key[i];
 518                 if (c == '.')
 519                         dot = 1;
 520                 /* Leave the extended basename untouched.. */
 521                 if (!dot || i > store.baselen) {
 522                         if (!isalnum(c) || (i == store.baselen+1 && !isalpha(c))) {
 523                                 fprintf(stderr, "invalid key: %s\n", key);
 524                                 free(store.key);
 525                                 ret = 1;
 526                                 goto out_free;
 527                         }
 528                         c = tolower(c);
 529                 }
 530                 store.key[i] = c;
 531         }
 532         store.key[i] = 0;
 533
 534         /*
 535          * The lock_file serves a purpose in addition to locking: the new
 536          * contents of .git/config will be written into it.
 537          */
 538         fd = open(lock_file, O_WRONLY | O_CREAT | O_EXCL, 0666);
 539         if (fd < 0 || adjust_shared_perm(lock_file)) {
 540                 fprintf(stderr, "could not lock config file\n");
 541                 free(store.key);
 542                 ret = -1;
 543                 goto out_free;
 544         }
 545
 546         /*
 547          * If .git/config does not exist yet, write a minimal version.
 548          */
 549         in_fd = open(config_filename, O_RDONLY);
 550         if ( in_fd < 0 ) {
 551                 free(store.key);
 552
 553                 if ( ENOENT != errno ) {
 554                         error("opening %s: %s", config_filename,
 555                               strerror(errno));
 556                         ret = 3; /* same as "invalid config file" */
 557                         goto out_free;
 558                 }
 559                 /* if nothing to unset, error out */
 560                 if (value == NULL) {
 561                         ret = 5;
 562                         goto out_free;
 563                 }
 564
 565                 store.key = (char*)key;
 566                 store_write_section(fd, key);
 567                 store_write_pair(fd, key, value);
 568         } else{
 569                 struct stat st;
 570                 char* contents;
 571                 int i, copy_begin, copy_end, new_line = 0;
 572
 573                 if (value_regex == NULL)
 574                         store.value_regex = NULL;
 575                 else {
 576                         if (value_regex[0] == '!') {
 577                                 store.do_not_match = 1;
 578                                 value_regex++;
 579                         } else
 580                                 store.do_not_match = 0;
 581
 582                         store.value_regex = (regex_t*)malloc(sizeof(regex_t));
 583                         if (regcomp(store.value_regex, value_regex,
 584                                         REG_EXTENDED)) {
 585                                 fprintf(stderr, "Invalid pattern: %s\n",
 586                                         value_regex);
 587                                 free(store.value_regex);
 588                                 ret = 6;
 589                                 goto out_free;
 590                         }
 591                 }
 592
 593                 store.offset[0] = 0;
 594                 store.state = START;
 595                 store.seen = 0;
 596
 597                 /*
 598                  * After this, store.offset will contain the *end* offset
 599                  * of the last match, or remain at 0 if no match was found.
 600                  * As a side effect, we make sure to transform only a valid
 601                  * existing config file.
 602                  */
 603                 if (git_config(store_aux)) {
 604                         fprintf(stderr, "invalid config file\n");
 605                         free(store.key);
 606                         if (store.value_regex != NULL) {
 607                                 regfree(store.value_regex);
 608                                 free(store.value_regex);
 609                         }
 610                         ret = 3;
 611                         goto out_free;
 612                 }
 613
 614                 free(store.key);
 615                 if (store.value_regex != NULL) {
 616                         regfree(store.value_regex);
 617                         free(store.value_regex);
 618                 }
 619
 620                 /* if nothing to unset, or too many matches, error out */
 621                 if ((store.seen == 0 && value == NULL) ||
 622                                 (store.seen > 1 && multi_replace == 0)) {
 623                         ret = 5;
 624                         goto out_free;
 625                 }
 626
 627                 fstat(in_fd, &st);
 628                 contents = mmap(NULL, st.st_size, PROT_READ,
 629                         MAP_PRIVATE, in_fd, 0);
 630                 close(in_fd);
 631
 632                 if (store.seen == 0)
 633                         store.seen = 1;
 634
 635                 for (i = 0, copy_begin = 0; i < store.seen; i++) {
 636                         if (store.offset[i] == 0) {
 637                                 store.offset[i] = copy_end = st.st_size;
 638                         } else if (store.state != KEY_SEEN) {
 639                                 copy_end = store.offset[i];
 640                         } else
 641                                 copy_end = find_beginning_of_line(
 642                                         contents, st.st_size,
 643                                         store.offset[i]-2, &new_line);
 644
 645                         /* write the first part of the config */
 646                         if (copy_end > copy_begin) {
 647                                 write(fd, contents + copy_begin,
 648                                 copy_end - copy_begin);
 649                                 if (new_line)
 650                                         write(fd, "\n", 1);
 651                         }
 652                         copy_begin = store.offset[i];
 653                 }
 654
 655                 /* write the pair (value == NULL means unset) */
 656                 if (value != NULL) {
 657                         if (store.state == START)
 658                                 store_write_section(fd, key);
 659                         store_write_pair(fd, key, value);
 660                 }
 661
 662                 /* write the rest of the config */
 663                 if (copy_begin < st.st_size)
 664                         write(fd, contents + copy_begin,
 665                                 st.st_size - copy_begin);
 666
 667                 munmap(contents, st.st_size);
 668                 unlink(config_filename);
 669         }
 670
 671         if (rename(lock_file, config_filename) < 0) {
 672                 fprintf(stderr, "Could not rename the lock file?\n");
 673                 ret = 4;
 674                 goto out_free;
 675         }
 676
 677         ret = 0;
 678
 679 out_free:
 680         if (0 <= fd)
 681                 close(fd);
 682         if (config_filename)
 683                 free(config_filename);
 684         if (lock_file) {
 685                 unlink(lock_file);
 686                 free(lock_file);
 687         }
 688         return ret;
 689 }
 690
 691